The present invention relates to extrusion of fat-containing confectionery products and particularly to extrusion of chocolate.
Fat-containing confectionery products, generally, are prepared from fats, including fat fractions and fat-substitutes, and may include sugar, milk-derived components, and solids from vegetable or cocoa sources in various proportions.
In general, chocolate products, which may be divided into groups of plain, or dark, chocolate and milk chocolates, including white chocolate, have a moisture content less than about 5% by weight. Plain chocolate typically is obtained by mixing sugar, cocoa butter (and optionally other fats and/or fat fractions and/or fat substitutes) and cocoa mass. Milk chocolate contains milk fat and non-fat milk solids (and optionally vegetable fat and/or fat fractions and/or fat substitutes) as additional ingredients. White chocolate contains milk fat and non-fat milk solids, sugar and cocoa butter (and optionally other fats and/or fat fractions and/or fat substitutes) without the addition of cocoa mass.
Although extrusion of various confectionery products is known, processes to effect such generally require employment of cooling and heating devices auxiliary and/or integral with the extrusion apparati, and although extrusion and pressing of chocolate have been mentioned in the art, such as in British Complete Specifications Nos. 223,362, 385,571 and 1 604 585, it is not believed that such has found application, particularly in a commercial mass production setting, without the aid of heating and cooling devices.
In the British '362 Specification, a process is disclosed for forming chocolate coverings or containers suitable for being filled, wherein solid bulk chocolate is forced under "high pressure" through an extrusion tube-forming die. It is taught that the temperature of the chocolate being processed which is generated by friction during compression in the die, is to be reduced by circulation of a cooling fluid in the die to maintain a "suitable" degree of plasticity within the die so that the chocolate is extruded in a hard, dense, non-porous condition.
In the British '571 Specification, a process is disclosed for manufacturing a tubular strip of chocolate, wherein a chocolate mass is introduced into a tube press similar to that which had been used for pressing cold macaroni and biscuit doughs, but provided with a heating jacket to heat the chocolate mass to a temperature of from 28.degree. C. to 32.degree. C., and the heated mass is pressed to mold it.
In the British '585 Specification, a process is disclosed for forming net-like products, wherein chocolate is tempered to a temperature of from 28.degree. C. to 31.degree. C. to provide viscosity properties which enable it to be extruded. The product extruded is cooled immediately to 15.degree. C. to 20.degree. C. after emerging from the die.
Typically, however, in a commercial production setting, chocolate products are prepared by mixing the chocolate ingredients and then grinding the mixture to a paste before conching at temperatures from 50.degree. to 85.degree. C. for periods of time of from a few hours to a few days, depending on the type of product and the equipment used. The conched chocolate then is cooled for tempering it, whereby glycerides are crystallized so the chocolate may acquire a stable condition when subsequently set. Cooling is carried out to achieve a tempering temperature on the order of from about 27.degree. C. to about 33.degree. C., depending upon the chocolate composition and character, particularly with a view to fat content. The tempering provides a flowable and pourable pasty mass, and in the usual production setting, because of viscosity considerations, the tempered chocolate is immediately directed to a molding or enrobing operation to prepare final products, after which, the products set.
As is known in the art, because of tempering, when the temperature of a set chocolate is increased above the final tempering temperature, the chocolate will remain solid up to a certain temperature above that final tempering temperature, and will not assume a pourable characteristic until it reaches a certain temperature in excess of the final tempered temperature. That is, the pour point of the chocolate has been altered by setting after tempering, and as the temperature of such chocolate is progressively increased above a temperature at which it was tempered, it softens due to partial melting of the fats until, again depending on the composition of the chocolate, it reaches its new pour point, whereat the chocolate has a viscosity that is sufficiently low for it to be flowable and to be poured.
Thus, in the context of a commercial production setting, generally, since tempered chocolate should be used within a short time for final product preparation, various production problems, including production equipment coordination, and product losses may result. To enhance commercial production efficiency, seeding of tempered chocolate and holding it at elevated temperatures has been suggested. Still, however, final production formation requires cooling means, such as cooling tunnels. On the other hand, if the tempered chocolate is not formed into a final product prior to being set, auxiliary equipment must be employed to heat the set chocolate, if it is to be reformed into a different final product, and that product, too, then is best cooled for setting. Still, therefore, means for solving such problems still are sought, as are means to avoid the need to cool the final product, with such as a cooling tunnel, and its attendant expense in terms of equipment and energy requirements.